Comments on: The future http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/ I am an astronomer, writer, and skeptic. I likes reality the way it is, and I aims to keep it that way. My real name is Phil Plait, and I run the Bad Astronomy blog. Mon, 09 Nov 2009 05:41:47 -0600 http://wordpress.org/?v=2.8.4 hourly 1 By: Avi Chapman http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/comment-page-1/#comment-51271 Avi Chapman Fri, 19 Oct 2007 06:51:29 +0000 http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/#comment-51271 Sorry - should have said 'their's'. Sorry – should have said ‘their’s’.

]]> By: Avi Chapman http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/comment-page-1/#comment-51270 Avi Chapman Fri, 19 Oct 2007 06:50:36 +0000 http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/#comment-51270 Wow. That's some link. That magnetic-centrifugal balance theory of there's is the same one that the flat earth society uses on their website. Wow. That’s some link. That magnetic-centrifugal balance theory of there’s is the same one that the flat earth society uses on their website.

]]> By: Brian C http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/comment-page-1/#comment-51269 Brian C Sat, 13 Oct 2007 01:27:52 +0000 http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/#comment-51269 Ah yes, thank you. I was confusing energy with orbital speed. I'm impressed humans even came up with the idea, really. Oh this is entertaining, someone explains why this is impossible!!! with many exclaimation points!!! Looks like the idea has been around since 2001... <a href="http://www.greatdreams.com/earth_orbit.htm" rel="nofollow">http://www.greatdreams.com/earth_orbit.htm</a> Ah yes, thank you. I was confusing energy with orbital speed. I’m impressed humans even came up with the idea, really.

Oh this is entertaining, someone explains why this is impossible!!! with many exclaimation points!!! Looks like the idea has been around since 2001…

http://www.greatdreams.com/earth_orbit.htm

]]> By: Nigel Depledge http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/comment-page-1/#comment-51268 Nigel Depledge Fri, 12 Oct 2007 15:01:46 +0000 http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/#comment-51268 Brian C, if the Earth is robbed of some of its orbital energy, it will fall towards the sun, and thus speed up. I know this is counter-intuitive, but the energy of the orbiting body determines the radius of the orbit. Thus, although Venus and Mercury both orbit the Sun faster a than Earth does, they actually possess less orbital energy. The shorter period of their orbits is a function of the distance from the Sun and the relative masses of the two bodies. Thus, to raise an orbiting satellite from low-Earth orbit (typically about 200 - 300 km up) to geosynchronous orbit (about 36,000 km up) requires quite a significant boost, even though the lower orbit has a significantly shorter period (about 90 minutes as opposed to 24 hours). However, I believe that, if the gravitational slingshot is done the other way, the Earth can gain momentum from the asteroid and hence its orbit will widen. Brian C, if the Earth is robbed of some of its orbital energy, it will fall towards the sun, and thus speed up. I know this is counter-intuitive, but the energy of the orbiting body determines the radius of the orbit. Thus, although Venus and Mercury both orbit the Sun faster a than Earth does, they actually possess less orbital energy. The shorter period of their orbits is a function of the distance from the Sun and the relative masses of the two bodies.

Thus, to raise an orbiting satellite from low-Earth orbit (typically about 200 – 300 km up) to geosynchronous orbit (about 36,000 km up) requires quite a significant boost, even though the lower orbit has a significantly shorter period (about 90 minutes as opposed to 24 hours).

However, I believe that, if the gravitational slingshot is done the other way, the Earth can gain momentum from the asteroid and hence its orbit will widen.

]]> By: Brian C http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/comment-page-1/#comment-51267 Brian C Wed, 10 Oct 2007 04:52:56 +0000 http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/#comment-51267 Mr. Astronomer, One idea I've found exciting since it was proposed in a paper a few years back was the idea that - by slingshotting a small asteroid past the earth in a controlled way thousands of times over a very long period and thus robbing earth of orbital energy - it would be possible to slowly widen earth's orbit such that it would stay within the sun's habitable zone much longer than otherwise possible. Have you heard of the idea? What do you think? It might seem silly, but I like the idea of Earth hanging around a bit longer than nature intended. Mr. Astronomer,

One idea I’ve found exciting since it was proposed in a paper a few years back was the idea that – by slingshotting a small asteroid past the earth in a controlled way thousands of times over a very long period and thus robbing earth of orbital energy – it would be possible to slowly widen earth’s orbit such that it would stay within the sun’s habitable zone much longer than otherwise possible. Have you heard of the idea? What do you think? It might seem silly, but I like the idea of Earth hanging around a bit longer than nature intended.

]]> By: Pratik Patel http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/comment-page-1/#comment-51266 Pratik Patel Tue, 09 Oct 2007 20:31:22 +0000 http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/#comment-51266 We need to start the "Preserve the Earth" fund *right now*! Okay, I stole the idea from Dr. Who ("The End of the World"). But someone needs to pay for those force fields and you can sure as hell bet the UN, Congress, EU etc won't lift a finger. I'll throw down a $20 - anyone else? We need to start the “Preserve the Earth” fund *right now*! Okay, I stole the idea from Dr. Who (”The End of the World”). But someone needs to pay for those force fields and you can sure as hell bet the UN, Congress, EU etc won’t lift a finger. I’ll throw down a $20 – anyone else?

]]> By: barrayaran http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/comment-page-1/#comment-51265 barrayaran Tue, 09 Oct 2007 18:49:06 +0000 http://blogs.discovermagazine.com/badastronomy/2007/10/08/the-future/#comment-51265 Cool. FYI, there's a typo on the +6.9 billion years page -- it should read <i>escape <b>its</b> gravitational pull</i>, not <i> escape it's gravitational pull</i>. Cool.

FYI, there’s a typo on the
+6.9 billion years page — it should read escape its gravitational pull, not escape it’s gravitational pull.

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